The invention relates generally to an electric power grid and more specifically to control of capacitor bank switching in the power grid.
The basic structure of an electric power system comprises various hardware elements such as generators, transformers, and real-time monitoring equipment, and software such as power flow analysis software, fault detection software, and restoration software for generation, transmission, and distribution of electricity.
In general, power system operators ensure the quality of the power supplied to the customers by maintaining the load bus voltages within their permissible limits. Any changes to the system configuration or in power demands can result in higher or lower voltages in the system. This situation can be improved by reallocating the reactive power generated in the system by adjusting transformer taps, changing generator voltages, and by switching VAR sources such as capacitor banks or static VAR compensators (SVCs).
Capacitor banks in the power grid are often used to provide leading reactive power compensation or power factor correction. The use of capacitor banks has increased because they are relatively inexpensive, easy and quick to install, and can be deployed virtually anywhere in the network. Capacitor bank installation has other beneficial effects on the system such as: improvement of the voltage at the load, better voltage regulation, reduction of losses, and reduction or postponement of investments in transmission.
Optimizing capacitor bank switching helps electric delivery companies minimize the cost of installing and maintaining equipment on a distribution feeder and achieve better performance from the available capacitor banks. There are various algorithms available for optimizing capacitor bank switching. However, most of these algorithms are combined with voltage control algorithms and thus lead to long convergence times. Further most of these algorithms result in certain capacitor banks being switched on and off more times in a day than desired. Frequent switching of capacitor banks degrades switching contacts of the capacitor banks and increases maintenance requirements and decreases lifetime.
Therefore, there is a need for an improved optimization approach to capacitor bank switching.